Eddie Jones has the following categories for players. In his mind some are good club pros, others have the potential to play at international level but aren't quite there and then there is a small elite group who have hit the subjective barometer permitting them to play Test rugby.

Categories are largely arbitrary while challenges are handed out to test hunger and aptitude. Had Usain Bolt been a rugby player, he would have told him to work harder on his speed off the mark. You get the idea.

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So, in a roundabout way, we come to Danny Cipriani. Is he just a good club player in Jones' mind? Aged 30 he misses out on the second category reserved for the Marcus Smiths and Gabriel Ibitoyes of this world. And then there is the third, the Test match player.

After the season Cipriani has put together, it would be baffling if he is not included among the names printed on RFU-headed notepaper when Jones reveals his squad for the three-Test tour of South Africa on Thursday. He has talked of resting some of his British & Irish Lions contingent, but fatigue and injuries aside, Cipriani deserves to be on that list on merit, and not just through opportunity generated through unavailability.

He has been box office this season, constantly combining the unpredictable with the pragmatic. England's attack was blunt in the Six Nations but Cipriani would help bring some fire to a backline that barely sparked in the final three matches of the championship.

Talking to ESPN back in January, Cipriani was introspective but quietly frustrated by opinion he was a disruptive influence. Rather than talking about his past, he wanted to focus on the future, aided by a renewed calm, philosophical outlook.

In a way this is win-win for Jones. Pick him and if he fails the matter is put to bed. But should he succeed -- as I believe he would -- then England will have added another dimension to their Rugby World Cup charge.

Thursday could be a watershed moment for Cipriani, who is out of contract with Wasps at the end of the season. If he is included, the chances of him signing a deal with an Aviva Premiership club increase. If he is omitted, then suddenly the lure of France or further fields will become more tempting.

His Wasps teammate James Haskell is in a similar state of limbo; without a club he is keen to stay in the top flight to maintain England aspirations but his selection fate will give an insight into Jones' long-term vision. With the likes of Maro Itoje and Mako Vunipola likely to be rested and a lengthy injury list including Anthony Watson and Jonathan Joseph, frontline players will be missing from the squad.

Owen Farrell, right, is a candidate to lead England in South Africa as captain Dylan Hartley continues to battle concussion symptoms. David Rogers - RFU/The RFU Collection via Getty Images

Haskell is a safe option for Jones, he knows he will offer blood, sweat and repartee, but aged 33 and if omitted, we get an idea of how the 2019 squad will look.

England are not short of promising talent and capable players. With captain Dylan Hartley out with concussion, Jamie George, Luke Cowan-Dickie, Tom Dunn and Tommy Taylor are the next cabs off the rank. Hardly a paucity of resources.

Should Mako swap the Highveld for holiday, then loosehead options number Joe Marler, Ellis Genge -- one of the players of the season -- Beno Obano and Alec Hepburn. If Jones wants to look at options beyond Dan Cole at tighthead then Kyle Sinckler, Nick Schonert and Harry Williams loom into view.

The back row calls will be fascinating. Sam Simmonds should be tried at openside, while Tom Curry, Don Armand and Jack Willis need to travel. Chris Robshaw will likely start and then there is the return of big Billy Vunipola at No. 8, who will be keen to unleash the frustration of an injury-laden season on the Boks. Elsewhere in the scrum, how wonderful it would be to see Bath lock Dave Attwood included after his forays across the channel on loan in Toulon.

At scrum-half Dan Robson must travel alongside Ben Youngs and Danny Care with Cipriani challenging George Ford for the fly-half spot. Centre contenders include Ben Te'o, Henry Slade -- he deserves a start at outside centre -- and Henry Trinder with Jack Nowell, Jonny May and Denny Solomona contending for the wing berths. Elliot Daly should be given a shot at fullback but Mike Brown will always be one of Jones' favourites while he may also look at Gloucester's Jason Woodward, who has had such an impressive season.

Then there is Owen Farrell. Had Hartley been fit, Farrell could have been rested but with the captain sidelined, England need a new leader for South Africa and Farrell is best placed to guide England.

So, despite the fatigue, injuries and enforced rest, England will still pack a punch when they travel to South Africa. But they fly out on the back of three defeats on the bounce, and Jones knows they will need to hit the ground running, win first up in Johannesburg and put the Boks on the back foot.

Throw Cipriani into the mix and you have the X-Factor that England will so badly need to do just that.